Roll Rate Research Articles

Research Progress and Prospect of Mechanized Harvesting Technology in the First Season of Ratoon Rice

The first seasonal harvest technology of ratoon rice requires the least rolling with suitable stubble height required by agronomy when the ratoon rice is nearly mature. Mechanized harvesting in the first season of ratoon rice needs to finish harvesting, threshing, cleaning, straw treatment, grain transportation, grain collection and other processes at one time with a low rolling rate and low rolling degree. Limited by the production conditions such as wet and soft fields, and wet, thick and strong straw, harvest technology with high efficiency and a low rolling rate of ratoon rice in the first season has become the key technology and research focus affecting the yield of ratoon rice. In this paper, we analyzed the planting and popularization of ratoon rice in China, summarized the planting mode and agronomic characteristics of ratoon rice, highlighted the research status of mechanized harvesting equipment for the first season of ratoon rice, especially the specialized harvesters, and illustrated in detail the technical characteristics and research trends of key segments such as chassis, header, and processes such as threshing and cleaning, and straw and stubble treatment of ratoon rice harvesters. In addition, we summarized the application status and value of lightweight technology, performance monitoring and fault diagnosis technology, grain quality detection technology and automatic navigation technology of mechanized harvest in the first season, explained the main problems and reasons affecting the development of ratoon rice harvest mechanization in China, and illustrated the prospect of its research focus and tendency.

Drivers’ Visual Distraction Detection Using Facial Landmarks and Head Pose

Drivers’ distraction has been widely studied in the field of naturalistic driving studies. However, it is difficult to use traditional variables, such as speed, acceleration, and yaw rate to detect drivers’ distraction in real time. Emerging technologies have obtained features from human faces, such as eye gaze, to detect drivers’ visual distraction. However, eye gaze is hard to detect in naturalistic driving situations, because of low-resolution cameras, drivers wearing sunglasses, and so forth. Instead, head pose is easier to detect, and has correlation with eye gaze direction. In this study, city-wide videos are collected using onboard cameras from over 289 drivers representing 423 events. Head pose (pitch, yaw, and roll rates) are derived and fed into a convolutional neural network to detect drivers’ distraction. The experiment results show that the proposed model can achieve recall value of 0.938 and area under the receiver operating characteristic curve value of 0.931, with variables from five time slices (1.25 s) used as input. The study proves that head pose can be used to detect drivers’ distraction. The study offers insights for detecting drivers’ distraction and can be used for the development of advanced driver assistance systems.

Design of fin stabilizer controller during ship zig-zag motion

When a ship is sailing on the sea, the ship will have violent motions due to the influence of waves, and the roll is the most obvious influence. In order to further reduce roll, a design method of fin stabilizer based on Lyapunov stability theory is studied in this paper. The roll motion model of the ship is constructed, and the roll reduction is realized by state feedback controller. Here, Lyapunov stability theory is used to solve the feasible region of the controller. The controller gain is obtained by using the method of linear matrix inequality. Then, the controller parameter optimization based on optimal phase matching can be realized. The anti-rolling performance of the ship is evaluated by the simulation of zig-zag motion. When a ship is in a zig-zag motion, it will roll more violently than when it is in a straight course because it is constantly changing course. Therefore, it is more meaningful to use zig-zag motion shape to verify the performance of fin stabilizer. Compared with the existing methods, the roll reduction rate of the proposed method is significantly improved, which proves that the proposed method is effective.

Wideband Filtering Slot Antenna Design with Stable Gain Using Characteristic Mode Analysis.

A filtering slot antenna with a simple structure combination using characteristic mode analysis (CMA) is proposed. To realize filtering characteristics, characteristic magnetic currents of line and ring slots are analyzed and designed. Then, the folding-line slot and double-ring slot are selected to realize radiation null separately and combined to construct the basic slot antenna. By properly exciting the selected characteristic modes, a wide filtering bandwidth and a stable gain are obtained. To validate the design process, a prototype antenna with a finite ground plane of about 1.1 λ × 1.1 λ is designed and fabricated. Simulated and measured results agree well, which both show a sharping roll rate in the lower and higher frequency and a flat gain realization in the pass band. The filtering bandwidth is 32.7%, the out-of-band suppression level at the higher frequency is over 20 dB, and the gain in the working frequency varies from 3.9 to 5.2 dB.

Crash Test Methodology for Electric Scooters with Anthropomorphic Test Device (ATD) Riders

<div class="section abstract"><div class="htmlview paragraph">As micromobility devices (i.e., e-bikes, scooters, skateboards, etc.) continue to increase in popularity, there is a growing need to test these devices for varying purposes such as performance assessment, crash reconstruction, and design of new products. Although tests have been conducted across the industry for electric scooters (e-scooters), this paper describes a novel method for crash testing e-scooters with anthropomorphic test devices (ATDs) “riding” them, providing new sources for data collection and research. A sled fixture was designed utilizing a pneumatic crash rail to propel the scooters with an overhead gantry used for stabilization of the ATD until release just prior to impact. The designed test series included impacts with a 5.5-inch curb at varying incidence angles, a stationary vehicle, or a standing pedestrian ATD. Test parameter permutations included changing e-scooter tire sizes, impact speeds, and rider safety equipment. One of the primary focuses of this testing was to establish a methodology which provided consistency in not only impact speed but also ATD orientation and scooter-to-obstacle contact.</div><div class="htmlview paragraph">Over the course of this research, 23 tests were conducted, consisting of 14 curb impacts, five vehicle impacts, and four pedestrian ATD impacts. A SLICE Micro data acquisition system was rigidly mounted on the rear deck region of the scooter and recorded accelerations in the longitudinal, lateral, and vertical directions in addition to yaw, pitch, and roll rates at a frequency of 10 kHz. Tape switches were used as a redundant confirmation of impact speed in addition to high-speed camera views with a calibrated checkerboard for independent analyses. This paper describes the test methodology in detail, provides a summary of test observations, and discusses additional potential uses for such a test system.</div></div>

Rider control identification in cycling taking into account steering torque feedback and sensory delays

Experiments and human rider models were used to investigate bicycle balance and steering using visuo/vestibular motion and proprioceptive feedback taking into account sensory delays. An instrumented steer-by-wire bicycle designed and built at the TU Delft bicycle laboratory was used to investigate rider responses with and with reduced steering torque feedback. Steering responses and bicycle motions were measured perturbing balance with impulsive forces at the seat post. The rider was commanded to follow a straight lane at unstable (2.6 and 3.7 ) and stable speeds (4.5 and 5.6 ). Bicycle speed was controlled with an electric drive and cruise control. Balance and steering responses could well be captured by linear impulse response functions which were consistent across participants. The impulse response functions were used to develop neuromuscular control models capturing rider–bicycle interaction. The Carvallo–Whipple bicycle model was extended with rider inertia and an additional degree of freedom for the steer-by-wire system. Rider behaviour was modelled as a balance and heading controller. This controller used visuo/vestibular motion feedback of roll angle and roll rate, heading angle and heading rate, and proprioceptive feedback of steering angle, velocity and torque. Results showed that the rider model followed the necessary stability condition of steer into the fall and was capable of stabilising the bicycle. Sensory delays had a negative effect on the model fit, which was resolved with an internal model and prediction algorithm. A model without steer angle and steer velocity feedback could not well capture the human response at the highest speeds and the absence of torque feedback had similar effects for all speeds, supporting the relevance of steer angle and torque feedback in bicycle control.

Influence of process layouts of multi-roll solid-liquid cast-rolling bonding process on circumferential performance uniformity during fabricating metal cladding materials

The twin-roll casting (TRC) process is typically used to fabricate laminated metal cladding strips with rectangular cross-sections, and it has the advantages of short flow, low energy consumption, green environmental protection, etc. Recently, a twin-roll solid-liquid cast-rolling bonding (TRSLCRB) process was proposed based on the TRC process to fabricate metal cladding materials with round cross-sections. However, the nonuniformity of heat transfer and mass transfer along the circumferential direction finally influences the performance uniformity. Therefore, a multi-roll solid-liquid cast-rolling bonding (MRSLCRB) process was proposed integrating cast-rolling bonding technology and multi-roll groove rolling technology. The steady-state thermal resistance network was established, and the influences of nominal roll radius, groove radius, and molten pool height on the heat transfer and mass transfer were studied systematically. 3-D steady-state thermal-fluid coupled simulation models of twin-roll, three-roll, and four-roll layouts were established. The results indicate that increasing casting roll number can improve the nominal cast-rolling velocity, service life of the casting roll, temperature uniformity, strain uniformity, and strain rate uniformity through regulating the heat transfer and mass transfer. Considering the manufacturing feasibility, the MRSLCRB equipment based on the three-roll layout was designed. Cu/steel cladding bars with uniform circumferential performance were fabricated, and the forming mechanism was revealed. The multi-field coupled analysis method provides a way to control heat and mass transfer uniformity, and the successful attempts of various typical metal cladding materials inspire exploring new forming processes.

Quintessential constant-roll inflation

We investigate a single field model in the context of the constant-roll inflation in which inflaton moves down to the minimum point of the potential with a constant rate of rolling. We use a quintessential inflationary model obtained by a Lorentzian function which is dependent on the number of e-folds. We present the inflationary analysis for the model and find the observational constraints on the parameters space using the observations of CMB anisotropies i.e. the Planck and Keck/array datasets. We find the observationally acceptable values of the Width of the Lorentzian function as 0.3<Γ≤0.5 at the 68% CL and Γ≤0.3 at the 95% CL when ξ=120, |β|=0.02 and N=60. Also, we acquire the observationally favoured values of the amplitude of the Lorentzian function as 400<ξ≤600 at the 68% CL and ξ≤400 at the 95% CL when Γ=0.1, |β|=0.02 and N=60. Moreover, we study the model from the Weak Gravity Conjecture approach using the swampland criteria.

Enigmatic surface rolls of the Ellesmere Ice Shelf

Abstract The once-contiguous Ellesmere Ice Shelf, first reported in writing by European explorers in 1876, and now almost completely disintegrated, has rolling, wave-like surface topography, the origin of which we investigate using a viscous buckling instability analysis. We show that rolls can develop during a winter season (~ 100 d) if sea-ice pressure (depth-integrated horizontal stress applied to the seaward front of the Ellesmere Ice Shelf) is sufficiently large (1 MPa m) and ice thickness sufficiently low (1–10 m). Roll wavelength initially depends only on sea-ice pressure, but evolves over time depending on amplitude growth rate. This implies that a thinner ice shelf, with its faster amplitude growth rate, will have a shorter wavelength compared to a thicker ice shelf when sea-ice pressure is equal. A drawback of the viscous buckling mechanism is that roll amplitude decays once sea-ice pressure is removed. However, non-Newtonian ice rheology, where effective viscosity, and thus roll change rate, depends on total applied stress may constrain roll decay rate to be much slower than growth rate and allow roll persistence from year to year. Whether the viscous-buckling mechanism we explore here ultimately can be confirmed as the origin of the Ellesmere Ice Shelf rolls remains for future research.

Characterizing the suckling behavior by video and 3D-accelerometry in humpback whale calves on a breeding ground.

Getting maternal milk through nursing is vital for all newborn mammals. Despite its importance, nursing has been poorly documented in humpback whales (Megaptera novaeangliae). Nursing is difficult to observe underwater without disturbing the whales and is usually impossible to observe from a ship. We attempted to observe nursing from the calf’s perspective by placing CATS cam tags on three humpback whale calves in the Sainte Marie channel, Madagascar, Indian Ocean, during the breeding seasons. CATS cam tags are animal-borne multi-sensor tags equipped with a video camera, a hydrophone, and several auxiliary sensors (including a 3-axis accelerometer, a 3-axis magnetometer, and a depth sensor). The use of multi-sensor tags minimized potential disturbance from human presence. A total of 10.52 h of video recordings were collected with the corresponding auxiliary data. Video recordings were manually analyzed and correlated with the auxiliary data, allowing us to extract different kinematic features including the depth rate, speed, Fluke Stroke Rate (FSR), Overall Body Dynamic Acceleration (ODBA), pitch, roll, and roll rate. We found that suckling events lasted 18.8 ± 8.8 s on average (N = 34) and were performed mostly during dives. Suckling events represented 1.7% of the total observation time. During suckling, the calves were visually estimated to be at a 30–45° pitch angle relative to the midline of their mother’s body and were always observed rolling either to the right or to the left. In our auxiliary dataset, we confirmed that suckling behavior was primarily characterized by a high average absolute roll and additionally we also found that it was likely characterized by a high average FSR and a low average speed. Kinematic features were used for supervised machine learning in order to subsequently detect suckling behavior automatically. Our study is a proof of method on which future investigations can build upon. It opens new opportunities for further investigation of suckling behavior in humpback whales and the baleen whale species.

Wake Vortex Effects due to Horizontal Crossing at Any Angle

The effects of wake crossing at any horizontal angle, airspeed, and altitude are considered, focusing on crossing at cruise speeds at altitudes close to the tropopause. The roll effect is considered in two cases: 1) specification of the aileron deflection as a function of time that exactly compensates for the rolling moment induced on the crossing aircraft by the wake of the leading aircraft so that the crossing aircraft is undisturbed; and 2) in the case when the available roll control power is not sufficient to compensate completely for the wake induced rolling moment, the resulting roll rate and bank angle of the crossing aircraft are calculated as a function of time. The distinction between the two cases is made by a safe separating distance or safe separating time: beyond which, roll compensation 1) is possible; and below which, rolling motion 2) is unavoidable. Besides the roll acceleration, roll rate, and bank angle for the roll axis, the effects of wake crossing are also considered for the vertical axis, including the load factor, vertical velocity, and altitude change. The theory applies to any pair of aircraft and indicates the dependence on aircraft parameters, flight, and atmospheric conditions.

Effect of Residual Deformation Energy and Critical Heating Rate on Cubic Texture and Grain Growth Behavior of Severely Deformed Aluminum Foil.

To clarify the microstructure, grain size, and recrystallization behavior during different annealing processes with controlled heating rates, the aim of this study was to investigate the effect of residual deformation energy after cold rolling and critical heating rate on cubic texture components, and grain growth behavior of aluminum plate, which was subjected to severe deformation. The experimental results revealed that the stored energy can be inferred from a calculation that fast annealing (FA) for 30 s was 2.2 times as large as slow annealing (SA) at 320 °C, which provided the driving force for grain growth during subsequent heating and resulted in a significant coarsening of grains in the FA process. In contrast, the intensity of cubic texture in SA was significantly higher than that in the FA process. A critical heating rate of 50 °C/min had been obtained to produce a homogeneous microstructure and strong cubic texture during the annealing processes with controlled heating rates and was verified by experiment. The relationship of Δηsur > 0.02ηb was as a criterion used to determine whether abnormal grain growth happened in aluminum foil, while the grain size exceeded the thickness of aluminum foil by examined calculation.

Informal Coalitions and Legislative Agenda Setting in Mexico’s Multiparty Presidential System

ABSTRACTTo what extent can presidents exert gatekeeping power in opposition-led legislatures? Drawing on a study of roll rates in the Mexican Chamber of Deputies, where presidents lack legislative majorities and often face a legislature controlled by the opposition, this article argues that gatekeeping power is divided among multiple actors. It finds that presidents exert weak gatekeeping power over the agenda. While presidents and their parties are rarely defeated in votes related to presidential initiatives, they generally create stable, informal coalitions with opposition parties to pass their bills. Moreover, the agenda-setting power of the president and the president’s party is weaker with bills that originate in the legislative branch, where the party is occasionally rolled on legislative initiatives and during the amendment stage if it is not also the median party.

Cosmic Coincidences of Primordial-Black-Hole Dark Matter.

If primordial black holes (PBHs) contribute more than 10% of the dark matter (DM) density, their energy density today is of the same order as that of the baryons. Such a cosmic coincidence might hint at a mutual origin for the formation scenario of PBHs and the baryon asymmetry of the Universe. Baryogenesis can be triggered by a sharp transition of the rolling rate of inflaton from slow-roll to (nearly) ultraslow-roll phases that produce large curvature perturbations for PBH formation in single-field inflationary models. We show that the baryogenesis requirement drives the PBH contribution to DM, along with the inferred PBH mass range, the resulting stochastic gravitational wave background frequency window, and the associated cosmic microwave background tensor-to-scalar ratio amplitude, into potentially observable regimes.

Evaluation of the Application of Maximum Radius in Horizontal Curves Using Vehicle Dynamic Simulation

Most road design standards recommend using a spiral curve for transitions. The main advantages of using this curve are the gradual increase in the centrifugal force, creating a suitable space for presenting superelevation, and providing a correct perception of the curve for the driver. In this research, vehicle dynamic simulation software CarSim and TruckSim is used to assess the forces imposed on the vehicles. In this regard, 360 scenarios are considered for sedans, SUVs, and trucks, which consist of variations of the road geometry (simple or spiral horizontal curve), curve radius, and type and speed of the vehicle. In addition, the regression analysis is performed to examine the relationships between the lateral acceleration (as a dependent variable) and the vehicle speed, curve radius, and vehicle type (as independent variables). The results indicate that in all cases, safety in the spiral horizontal curve is greater than that in the simple horizontal curve, and the maximum side friction factor, lateral acceleration, roll rate, roll angle, yaw rate, and lateral distance in the simple horizontal curve are higher than those in the spiral horizontal curve. Moreover, the difference percentage of the side friction factor, lateral acceleration, yaw rate, and lateral distance between the simple and spiral horizontal curves is the highest in SUVs, followed by sedans and trucks, while the difference percentage of the roll rate and roll angle is the highest in sedans, followed by SUVs and trucks. The results of regression analysis illustrate that the coefficient of determination (R2) in the proposed model is 0.972, 0.964, and 0.981 for sedans, SUVs, and trucks, respectively, indicating the strong relationships between the dependent and the explanatory variables as well as the capability of the model to cover the data.

Eigen-structure problem optimization for multirate, multi-input multi-output systems applied to a roll rate autopilot

Abstract In this paper, an optimal solution to the eigen-structure problem that dramatically reduces the control effort required for a multi-input multi-output (MIMO) multirate system is proposed. This technique not only minimize the amplitude of state transmission and control signal changes but also reduce the sensitivity to the effects of internal sampling in multirate MIMO systems results from interactions of the model order reduction. In this study, a constrained eigen-structure method with nonlinear constraints is used. The novelty of this study is that by using partial derivatives, a gain optimization process to optimize the nonlinearly constrained eigen-structure method is proposed. First, this method is explained, and then the desired method is applied for optimization operations, and finally, the results will be shown with a numerical example and a simulation.

Baryogenesis from ultra-slow-roll inflation

The ultra-slow-roll (USR) inflation represents a class of single-field models with sharp deceleration of the rolling dynamics on small scales, leading to a significantly enhanced power spectrum of the curvature perturbations and primordial black hole (PBH) formation. Such a sharp transition of the inflationary background can trigger the coherent motion of scalar condensates with effective potentials governed by the rolling rate of the inflaton field. We show that a scalar condensate carrying (a combination of) baryon or lepton number can achieve successful baryogenesis through the Affleck-Dine mechanism from unconventional initial conditions excited by the USR transition. Viable parameter space for creating the correct baryon asymmetry of the Universe naturally incorporates the specific limit for PBHs to contribute significantly to dark matter, shedding light on the cosmic coincidence problem between the baryon and dark matter densities today.

Edge crack damage analysis of AZ31 magnesium alloy hot-rolled plate improved by vertical roll pre-rolling

In the present study, through vertical roll pre-rolling of AZ31 magnesium alloy hot-rolled plate at room temperature, the effect of different vertical roll pre-rolling reduction on edge crack of the plate during flat rolling was systematically studied. The evolution of microstructure and texture in the edge and middle of the plate after vertical roll pre-rolling, heating and rolling was analyzed by using EBSD technology. The results show that during the vertical roll pre-rolling, {10–12} primary twins and {10–12}-{10–12} secondary twins dominated the edge deformation, while {10–12} primary twins dominated the middle deformation. With the increase of vertical roll pre-rolling reduction, the twin volume fraction of the edge and the middle increased, and the difference between them decreased gradually. After heating, the twin orientation caused by vertical roll pre-rolling was still maintained, and there was a significant difference in grain size between the edge and the middle. When the reduction rate of flat rolling was 30%, cracks have already appeared in the initial plate, while the vertical roll pre-rolled samples showed extremely high rolling performance. When the reduction rate of flat rolling was 50%, the 8PR sample still had no crack initiation. In addition, after flat rolling of 50%, the initial plate showed a strong basal texture, while the maximum pole density of the 8PR plate was small, and the texture distribution was very scattered, showing the characteristics of weak orientation.

Lateral/Directional Control Law Design for Civil Airplane Based on Eigen Structure Assignment

Considering disadvantages of lateral/directional mode characteristics of civil aircraft, design requirements are thus presented and the P-Beta control law architecture is adopted for the lateral/directional control law. Meanwhile, the practical application of eigen structure assignment in the design of lateral/directional control law is studied. By eigen structure assignment the closed loop is designed, and the decoupling of roll channel and yaw channel is realized. Through the design of feed-forward command channel, the pilot’s stick control roll rate and pedal control sideslip angle are realized. Simulation results show that the designed lateral/directional flight control law could meet design requirements.

LMI-Based H∞ Controller of Vehicle Roll Stability Control Systems with Input and Output Delays.

Many of the current research works are focused on the development of different control systems for commercial vehicles in order to reduce the incidence of risky driving situations, while also improving stability and comfort. Some works are focused on developing low-cost embedded systems with enough accuracy, reliability, and processing time. Previous research works have analyzed the integration of low-cost sensors in vehicles. These works demonstrated the feasibility of using these systems, although they indicate that this type of low-cost kit could present relevant delays and noise that must be compensated to improve the performance of the device. For this purpose, it is necessary design controllers for systems with input and output delays. The novelty of this work is the development of an LMI-Based H output-feedback controller that takes into account the effect of delays in the network, both on the sensor side and the actuator side, on RSC (Roll Stability Control) systems. The controller is based on an active suspension with input and output delays, where the anti-roll moment is used as a control input and the roll rate as measured data, both with delays. This controller was compared with a controller system with a no-delay consideration that was experiencing similar delays. The comparison was made through simulation tests with a validated vehicle on the TruckSim® software.